Spinach, Mushroom & Pepper "Holiday" Stuffed Shells | epicuricloud (Tina Verrelli)

Ingredients

• 1 tablespoon olive oil
• 1/2 sweet onion (chopped)
• 8 ounces sliced crimini (baby bella) mushrooms (chopped)
• 1 teaspoon garlic (minced)
• 1 teaspoon Italian seasoning
• 1/2 teaspoon salt
• 1/4 teaspoon pepper
• 1/8 teaspoon red pepper flakes (optional)
• 1 (12-ounce) jar roasted red peppers (drained & chopped)
• 2 (10-ounce) boxes frozen chopped spinach (thawed & squeezed dry)
• 1 (30-ounce) container ricotta cheese (I use whole milk)
• 1/2 cup Parmesan cheese (grated)
• 1 egg
• 2 cups mozzarella (shredded & divided)
• 2 (24-ounce) jars marinara sauce ((or homemade))
• 1 (12-ounce) box jumbo shells pasta
• salt & water for boiling pasta